Real-time hemodynamic assessment of intracranial stenosis in a patient with orthostatic aphasia: Potential applications of transcranial Doppler

Abstract

BACKGROUND: Intracranial atherosclerotic stenosis is thought to be responsible for 8% of all ischemic stroke subtypes. Transcranial Doppler (TCD) ultrasonography allows for noninvasive and dynamic evaluation of the cerebral circulation within the circle of Willis. We present a case of recurrent, orthostatic transient ischemic attacks in which, using TCD, we were able to correlate dynamically between the orthostatic symptomatology and a significant drop in the mean flow velocity (MFV) across the stenotic middle cerebral artery (MCA) segment. METHODS: A 56-year-old male presented with recurrent episodes of orthostatic right-sided weakness and expressive aphasia. Diagnostic TCD revealed a stenotic signal in the left internal carotid artery (ICA) siphon. Subsequent TCD monitoring of both MCAs demonstrated a significant orthostatic drop in MFV of the left MCA, which closely correlated with his symptoms. The cerebral angiogram confirmed a high-grade stenosis at the supraclinoid segment of the left ICA. CONCLUSION: TCD is a useful, noninvasive, and dynamic tool for assessment of the intracranial circulation, and should be considered in the workup of patients with hypoperfusion cerebrovascular events. © 2008 by the American Society of Neuroimaging.